Identifying users who access Tor hidden services -- websites that are only accessible inside the Tor anonymity network -- is easier than de-anonymizing users who use Tor to access regular Internet websites.
Little is known about how U.S. and European law enforcement shut down more than 400 websites, including Silk Road 2.0, which used technology that hides their true IP addresses.
The Tor Project has flagged a server in Russia after a security researcher found it slipped in malware when users were downloading files.
The Russian Ministry of Interior is willing to pay 3.9 million roubles, or around US$111,000, for a method to identify users on the Tor network.
Developers of Tor software believe they've identified a weakness that was scheduled to be revealed at the Black Hat security conference next month that could be used to de-anonymize Tor users.